Generally speaking, to fill containment units of biological liquids such as stem cells, platelet concentrates, serum eye drops, plasma, etc . . . , devices of known type are used having means for the connection of a syringe containing the biological liquid and a plurality of containment units to be filled.
More in particular, these connection means define a transit channel for the biological liquid having an inlet gap, connectable to the syringe containing the biological liquid, and a plurality of outlet gaps, associable with the units to be filled.
These devices also comprise at least a mouth for expelling the air contained in the containment units, and aspired by means of a syringe. In fact, the containment units generally used with these devices of known type are of the soft or flexible type, i.e., deformable to such an extent as to make their opposite sides coincide with one another, so that by applying a suitable vacuum, they can be emptied of the air contained inside them, thereby making subsequent filling easier.
Some of these devices of known type are described by DE 19934491 and by EP 1930033.
These devices of known type do however have a number of drawbacks.
They are in fact complicated to make and assemble, also due to the high number of parts making them up.
Another drawback of these known devices consists in the fact that they take a long time to prepare. These long preparation times are due at least in part to the carrying out of the air aspiration and biological liquid filling phases, which may even have to be repeated several times in order to eliminate as much air as possible, and to the handling of the devices themselves aimed at facilitating the movement of the air bubbles towards the outlet mouth.
Another problem still of devices of known type consists in the fact that they do not allow the easy preparation of a high number of containment units, e.g., more than twenty units, due to the ensuing difficulty in handling same.
Furthermore, the larger the number of containment units to be filled, the greater the dimensions must be of the connecting elements placed between the syringe and the containment units themselves, hence the biological liquid which remains inside such connecting elements and which is wasted increases along with the increase in the number of units to be filled.
Another drawback of known devices consists in the fact that they can only be used with containment units of a soft or flexible type, i.e., whose walls are deformable until they coincide with one another.
The devices of known type cannot therefore be used with semi-rigid containment units, i.e., deformable but not enough to cause their collapse, although preferable to soft bags inasmuch as they permit controlling the dispensing of the biological liquid towards the outside in a more precise and easier way.
More in detail, the semi-rigid units are not used with the aforementioned devices of known type inasmuch as they cannot be completely emptied of the air contained inside them, and which therefore prevents them from being completely filled. The biological liquid introduced into the transit channel by the syringe manages to return up towards the semi-rigid containment units only along a section of the channel itself due to the presence of air which prevents it from moving any further forward.
It therefore follows that the devices of known type for filling containment units of biological liquids, such as stem cells, platelet concentrates, serum eye drops, plasma, etc . . . , have a range of application limited only to the use of flexible containment units, which are however to be considered worse than the semi-rigid type inasmuch as they do not permit the controlled dispensing of the biological liquid itself.